There is a general desire in the art of display technology to provide displays with high-resolution as measured in a number of imaging elements per unit area of the display surface and to provide displays that are low in cost. These objectives can be difficult to achieve in a single display. In particular, it is conventionally known to form a display device by depositing a plurality of individual light emitting materials in a pattern on a surface. These deposits of light emitting material are adapted to radiate light when exposed to electrical energy and are referred to herein as light emitting elements. Control electronics are also deposited on the surface of such a display that enable a controller to selectively provide a controlled amount power to each image display element. Such control circuits are generally known in the art as a “backplane”.
It will be appreciated that both the light emitting elements and backplane require a certain amount of the space on the surface. As the number of light emitting elements increases, there is a concomitant need for an ever-larger number of control lines in the backplane. However, as the number of light emitting elements per unit area on a display increases, there is a decrease in available space between light emitting elements for the control lines and other circuits of the backplane. Therefore, as the number of light emitting elements in the display increases, it becomes substantially more difficult to define a backplane on the same surface as the light emitting elements.
One way to solve this problem is to the form a display using a plurality of layers. In a first layer formed on the surface, light emitting elements are formed on the surface in a first layer and a second layer is overlaid onto the first layer with the second layer having backplane circuits arranged to cooperate with the light emitting elements of the imaging plane. This approach can cause a variety of problems. For example, inter-layer registration problems become difficult to solve in high-resolution displays. This is because as the size of the light emitting elements is reduced it becomes increasingly difficult to align the circuits of the backplane with appropriate light emitting elements formed as another layer on the surface. Further, the forming of multiple layers adds assembly steps and introduces the possibility of damaging the light emitting elements in the process of applying the backplane. It will be appreciated that, even a single damaged light emitting element in a display can introduce an artifact in a displayed image that renders the display unsatisfactory for use by a consumer.
There is also desire in the art to form displays using non-conventional surfaces such as flexible substrates. One barrier to the development of displays on flexible substrates is that it is difficult to maintain the integrity of the relationship between the backplane and the light emitting elements when the surface upon which they are formed can be deformed. Further, there is a desire to form displays using non-flat surfaces such as curved or non-flat contours, fabrics, bottles, and the like as substrates, however, it is difficult to form backplanes using such surfaces.
Accordingly what is needed in the art an imaging element that can be used to make displays without requiring complex backplane structures. What is also needed in the art is an imaging element that can be used to make displays on non-conventional surfaces and/or flexible surfaces.